Structured oxidation catalysts

Abstract

Structured catalysts useful for oxidizing alkanes, alkenes and combinations of alkanes and alkenes are described. The structure catalysts comprise one or more mixed metal oxide catalysts having a three dimensional structure that is self-supporting and that facilitates movement of gas phase reactants and products and one or more mixed metal oxide catalysts deposited on a three dimensional form of continuous unitary structures having openings that facilitates movement of gas phase reactants and products.

1 . A structured catalyst comprising: one or more mixed metal oxide catalysts, each catalyst sequentially deposited as essential elements, in random order, the relative amounts of elements satisfying the expression  
       MoV a Nb b X c Z d O n    
     wherein X is at least one element selected from the group consisting of Te and Sb, Z is at least one element selected from the group consisting of W, Cr, Ta, Ti, Zr, Hf, Mn, Re, Fe, Ru, Co, Rh, Ni, Pd, Pt, Ag, Zn, B, Al, Ga, In, Ge, Sn, Si, Pb, P, Bi, Y, Ce, rare earth elements and alkaline earth elements, 0.1≦a≦1.0, 0.01≦b≦1.0, 0.01≦c≦1.0, 0≦d≦1.0 and n is determined by the oxidation states of the other elements; wherein the one or more metal oxide catalysts are self-supporting and further comprise a three dimensional structure having openings that facilitates movement of gas phase reactants and products.  
   
   
       2 . The structured catalyst according to  claim 1 , wherein the one or more mixed metal catalysts are deposited by chemical vapor deposition, physical vapor deposition and combinations thereof, resulting in a porous catalyst.  
   
   
       3 . A structured catalyst comprising: one or more mixed metal oxide catalysts, each catalyst satisfying the expression  
       MoV a Nb b X c Z d O n    
     wherein X is at least one element selected from the group consisting of Te and Sb, Z is at least one element selected from the group consisting of W, Cr, Ta, Ti, Zr, Hf, Mn, Re, Fe, Ru, Co, Rh, Ni, Pd, Pt, Ag, Zn, B, Al, Ga, In, Ge, Sn, Si, Pb, P, Bi, Y, Ce, rare earth elements and alkaline earth elements, 0.1≦a≦1.0, 0.01≦b≦1.0, 0.01≦c≦1.0, 0≦d≦1.0 and n is determined by the oxidation states of the other elements, in contact with a three dimensional form of continuous unitary structures having openings that facilitate movement of gas phase reactants and products; wherein the three dimensional form of continuously unitary structures comprise ceramic foams and ceramic monoliths selected from the group consisting of cordierite, alumina, zirconia, silica, aluminosilicate zeolites, phosphosilicate zeolites, other zeolites and combinations thereof, and wherein the one or more mixed metal oxide catalysts are deposited on the ceramic foams and ceramic monoliths by methods selected from the group consisting of impregnation, wash coating, slurry dip-coating, chemical vapor deposition, physical vapor deposition, precipitation and combinations thereof.  
   
   
       4 . The structured catalysts according to claims  1  or  3 , wherein the structured catalysts are fabricated in the form of a microreactor or arrays of microreactors having mechanically produced openings selected from the group consisting of pores, cells, channels, and other narrow passages.  
   
   
       5 . A modified structured catalyst comprising: one or more mixed metal oxide catalysts, each catalyst sequentially deposited as essential elements, in random order, the relative amounts of elements satisfying the expression  
       MoV a Nb b X c Z d O n    
     wherein X is at least one element selected from the group consisting of Te and Sb, Z is at least one element selected from the group consisting of W, Cr, Ta, Ti, Zr, Hf, Mn, Re, Fe, Ru, Co, Rh, Ni, Pd, Pt, Ag, Zn, B, Al, Ga, In, Ge, Sn, Si, Pb, P, Bi, Y, Ce, rare earth elements and alkaline earth elements, 0.1≦a≦1.0, 0.01≦b≦1.0, 0.01≦c≦1.0, 0≦d≦1.0 and n is determined by the oxidation states of the other elements; wherein the modified catalyst is self-supporting and further comprises a three dimensional structure having openings that facilitates movement of gas phase reactants and products; and wherein at least one catalyst is modified using one or more chemical treatments, one or more physical treatments and one or more combinations of chemical and physical treatments.  
   
   
       6 . The modified structured catalysts of  claim 5  wherein one or more modified mixed metal catalysts are deposited on a three dimensional form of continuously unitary structures comprising ceramic foams and ceramic monoliths, selected from the group consisting of cordierite, alumina, zirconia, silica, aluminosilicate zeolites, phosphosilicate zeolites, other zeolites and combinations thereof, by methods selected from the group consisting of impregnation, wash coating, slurry dip-coating, chemical vapor deposition, physical vapor deposition, precipitation and combinations thereof.  
   
   
       7 . A process for improving one or more performance characteristics of one or more mixed metal oxide catalysts, comprising the steps of: 
 a) depositing one or more metal oxide catalysts as a self-supporting structured catalyst or on a three dimensional form of continuous unitary structures having openings that facilitate movement of gas phase reactants and products; and optionally b) treating the structured catalyst with one or more chemical treatments, one or more physical treatments and one or more combinations of chemical and physical treatments.    
   
   
       8 . A process for preparing a structured catalyst comprising the step of depositing one or more mixed metal oxide catalysts, each catalyst deposited as essential elements in random order satisfying the expression  
       MoV a Nb b X c Z d O n    
     wherein X is at least one element selected from the group consisting of Te and Sb, Z is at least one element selected from the group consisting of W, Cr, Ta, Ti, Zr, Hf, Mn, Re, Fe, Ru, Co, Rh, Ni, Pd, Pt, Ag, Zn, B, Al, Ga, In, Ge, Sn, Si, Pb, P, Bi, Y, Ce rare earth elements and alkaline earth elements, 0.1≦a≦1.0, 0.01≦b≦1.0, 0.01≦c≦1.0, 0≦d≦1.0 and n is determined by the oxidation states of the other elements, wherein the structured catalyst produced is self-supporting and facilitates movement of gas phase reactants and products or by depositing the one or more mixed metal oxide catalysts on a three dimensional form of continuous unitary structures having openings that facilitate movement of gas phase reactants and products.  
   
   
       9 . A process for producing C 2 -C 8  oxygenates, including C 2 -C 8  unsaturated carboxylic acids, which comprises the step of contacting a corresponding alkane, alkene or a mixture of corresponding alkane and alkene to a vapor phase catalytic oxidation reaction with a structured catalyst comprising one or more mixed metal oxide catalysts; wherein yield and selectivity of the oxygenates, including unsaturated carboxylic acids, is improved using the structured catalyst as compared to the one or more corresponding unmodified mixed metal oxide catalysts.  
   
   
       10 . A process for producing C 2 -C 8  oxygenates, including C 2 -C 8  unsaturated carboxylic acids, which comprises the steps of: 
 a) modifying a structured catalyst comprising one or more mixed metal oxides using one or more chemical treatments, one or more physical treatments and one or more combinations of chemical and physical treatments; and    b) contacting a corresponding alkane, alkene or a mixture of corresponding alkane and alkene to a vapor phase catalytic oxidation reaction with the modified structured catalyst;    wherein yield and selectivity of the oxygenates, including unsaturated carboxylic acids, is improved using the one or more modified structured catalysts as compared to the one or more corresponding unmodified structured catalysts.